1. Field of the Invention
The present invention relates generally to the maintenance of seawalls disposed between bodies of water and retained earth and, more particularly, to methods and apparatus for maintaining seawalls using anchoring devices to strengthen the seawalls to resist potential damage and/or repair actual damage in the seawalls.
2. Discussion of the Related Art
Seawalls are commonly disposed between bodies of water and earth to provide physical boundaries between the bodies of water and the earth and to support or retain the earth by resisting the pressure of the retained earth against the seawalls. Seawalls can be used to separate earth from various types of bodies of water of various sizes and depths. Seawalls can be constructed in various ways and of various materials. Typically, seawalls have a vertical span or height sufficient for an upper end of the seawall to normally extend above the water with a lower end or toe portion of the seawall embedded in the earthen floor to extend below the body of water. The distance that a seawall extends above the water may vary depending on the height of the retained earth above the water and/or anticipated fluctuations in water level. The depth to which the embedded toe portion extends below the water may vary in accordance with the vertical span of the seawall and/or the depth of the body of water to provide sufficient support for the seawall to resist movement from the pressure of the retained earth against the seawall. Accordingly, seawalls are usually designed for a particular depth body of water. The thickness of seawalls may vary depending on site-specific loads and other engineering parameters. One representative type of seawall comprises concrete panels about ten to fifteen feet high, about four feet wide and about three to five inches thick disposed in side by side abutment to form a continuous wall.
Since the earth exerts greater pressure against seawalls than the water, seawalls are oftentimes damaged or destabilized during their lifetimes as evidenced, for example, by movement, displacement, shifting, cracking and/or misalignment of the seawalls. Sometimes seawalls are placed at risk for damage or instability due to a change in conditions occurring subsequent to installation of the seawalls. For instance, if a body of water is dredged resulting in a greater depth body of water and a lesser depth of penetration for the toe portion of an existing seawall, the lesser depth of penetration for the toe portion may no longer be sufficient for the seawall to support the pressure of the retained earth such that the seawall is susceptible to damage or instability. In some cases, the height of the retained earth on the earth facing side of an existing seawall may be increased, causing increased pressure of retained earth against the seawall by which the seawall may be damaged or destabilized. In addition to the pressures of retained earth, seawalls may be damaged or destabilized directly or indirectly due to other conditions including collisions or other impacts, corrosion, environmental factors, and age. Since removal and replacement of damaged and/or unstable seawalls involves significant cost and disruption, it is preferable to strengthen existing seawalls to repair and/or avoid damage or instability.
It has been proposed to strengthen seawalls to resist movement using anchors or tie rods in conjunction with cementitious material as represented by U.S. Pat. No. 1,270,659 to Ravier, U.S. Pat. No. 4,480,945 to Schnabel, Jr., U.S. Pat. No. 4,711,604, to Heimsoth et al., and U.S. Pat. No. 4,728,225 to Brandl et al. U.S. Pat. No. 3,371,494 to Lagerstrom, U.S. Pat. No. 4,253,781 to Fischer et al., and U.S. Pat. No. 4,911,582 to Pierce, Jr. et al. disclose the use of anchors or tie rods in conjunction with cementitious material to restrain structural walls other than seawalls. Helical anchors for building constructions are represented by U.S. Pat. No. 4,499,698 to Hoyt et al., U.S. Pat. No. 5,011,366 to Hamilton, et al., U.S. Pat. No. 5,120,163 to Holdeman et al., U.S. Pat. No. 5,139,368 and U.S. Pat. No. 5,171,107 to Hamilton et al., U.S. Pat. No. 5,213,448 to Seider et al., and U.S. Pat. No. 5,927,905 to van Halteren.
Prior apparatus and methods for repairing and/or strengthening seawalls and other retaining walls have various disadvantages including complicated structure and installation steps, major disruption, the need for excavating and/or disturbing the earth, partial or complete demolition of existing walls, the need to temporarily hold back or contain water during installation, the need to install additional and/or replacement wall structure, the use of cementitious material to assist in anchoring, the need for backfill, and the inability to execute installation from a body of water. Prior apparatus and methods which require earth-side access are untenable where homes or other buildings are situated close to seawalls making it undesirable and even prohibitive to disturb the earth on the earth facing sides of the seawalls and/or to conduct seawall maintenance from the earth facing sides. Prior apparatus and methods for repairing and/or strengthening seawalls and other retaining walls using anchors or tie rods generally lack the ability to rigidly interconnect a plurality of spaced anchors or tie rods installed in a wall to maintain the spacing between the anchors or tie rods in a desired direction. Furthermore, prior apparatus and methods for repairing and/or maintaining seawalls and other retaining walls using anchors or tie rods do not allow a plurality of spaced anchors or tie rods installed in a wall to be adjustably interconnected to adjust the spacing between the anchors or tie rods. Prior apparatus and methods for repairing and/or strengthening seawalls and other retaining walls do not contemplate closing openings in the walls by adjustably moving the walls between interconnected anchors or tie rods installed in the walls on opposite sides of the openings.
Accordingly, there is a need for apparatus and methods for maintaining seawalls by repairing and/or strengthening the seawalls utilizing anchoring devices having anchoring members installed from the water facing sides of the seawalls to extend through the seawalls into the retained earth and retaining members secured to the anchoring members along the water facing sides of the seawalls without the need for excavation and/or disturbance of the earth, removal of existing seawalls or seawall portions and/or the installation of additional seawalls or seawall portions, and without the need for backfill, cementitious material and water containment while having simplified structure and installation steps. There is also a need for apparatus and methods for maintaining seawalls by which at least a pair of spaced anchoring members extending through a seawall may be rigidly secured in interconnected relation to maintain the spacing between the interconnected anchoring members. Another need exists for apparatus and methods for maintaining seawalls by which at least a pair of spaced anchoring members extending through a seawall may be adjustably interconnected to adjust the spacing between the interconnected anchoring members. A need further exists for apparatus and methods for maintaining seawalls by which anchoring members installed in a seawall on opposite sides of an opening in the seawall may be interconnectedly drawn toward one another to close the opening.